A difficult environment typical to this application is the transport of tool sets into a high pressure hydraulic compaction press whose hydraulic systems apply hydraulic pressures in excess of 5,000 psi to the main piston of the hydraulic press. These pressures can generate 1,000 to 10,000 tons of force on the tooling anvils of the tool set and result in a high ratio of force on the product contained in the belt portion of the tool set. In one instance the pressed products are industrial diamonds. See U.S. Pat. No. 4,309,893. Actual force on the product may vary from 750,000 to 1,000,000 psi. Occasionally during a pressing cycle the anvils or some other part of the tooling will fail while the press is operating at full tonnage. Such failure will allow collapse of the anvils resulting in decompression of the press main cylinder and causing sudden release of the stored energy within the press structure. Therefore, damaged parts of the tooling may act like missiles endangering life and property. Consequently, the press structure or die space must be enclosed. Therefore, the transport system must be designed so as to deliver the tool set into the press through sliding access doors which will open to receive the tooling and close when the tooling is in place.
There are other considerations of environment and the process required to produce industrial diamonds that affect the design and operation of the tool transport system. To effect a seal in the high pressure chamber of the tooling pyrolitic material is used. This material and the end product, such as diamonds, is highly abrasive. These materials will cause severe wear to any moving parts and interfere with electrical relays, contacts, seals, hose connections and like parts.
The diamond process requires a recipe of carbon and suitable catalysts subjected to pressure and heat for controlled periods of time. In the diamond synthesis process, an inductive electrical current is passed via bus bar conductor through the upper anvil into the recipe and out through the lower anvil creating a circuit and heating the carbon recipe contained in the belt. A combination of heat 1,500 to 1,700 degrees, approximately 800,000 psi, and time cause a transformation of carbon into diamonds. Due to radiation and conduction of heat, the belt portion of the tooling rises above room temperature requiring the use of cooling water to control belt temperature.
Other operation requirements of the tool transport system is an ability to handle two tool sets for each press, provide a recipe load station, provide a knock-out station to remove the finished product, and, in some cases, an idle station. Two tool sets are used so that while one set is in the press, the second tool set is being prepared for the next production cycle. There are two transport system concepts that can be employed to handle two sets of tool sets. One concept uses two individual transport systems, each of which delivers a tool set to a different side of the press die space. The second concept delivers each tool set to the same side of the press die space. This second concept is feasible if a turntable unit is used along with an optional idle station It is the second concept, a turntable concept which is the subject of this invention, and, for the purpose of description in this application, this concept will be referred to as a single opening system, or alternatively, as a turntable system. There are a number of advantages in a single opening concept. Only one transport system is required to insert two tool sets. Another advantage is that one knock-out press can jointly serve two presses and four tool sets, whereas a dual opening system generally requires one knock-out system per press.
As has been previously described, the transport system include a method of inserting two tool sets into a single press opening and provide a number of external stations to perform other functions. For the purpose of this application, the preferred embodiment consists of two carriages, one for each tool set, a turntable and two or more external stations. The turntable, press stations, and external stations all have a pair of parallel rails upon which the carriages can traverse to deposit or carry the tool sets to each station.
Various methods have been used to rotate the turntable to each station and drive the carriages linearly along the tracks to each station.
One rotational method to index the turntable is a hydraulically driven pinion and ring gear, which one skilled in the art will comprehend. Two of the most frequently used carriage linear drives used have been cylinder push-pull and rack-and-pinion. All of the foregoing indexing and linear drives have experienced numerous problems due to excessive wear or malfunction of moving parts, seals, etc., because of the abrasive environment described above Accurate rotational indexing has been difficult and unreliable due to heavy outboard rotating mass and breakdown of position-indicating limit switches. The problems have been further exacerbated by the necessity of supplying hydraulic, electrical and water services to the travelling carriages. These service lines, limit switches, joints, seals, contacts, and connections have worn prematurely due to the dirty environment and the abrasive nature of the product.
It is therefore a paramount objective of the present invention to provide a turntable system that permits transport and delivers two tool sets to a single opening face of a press while providing a multiple of external work stations.
Another but equally important objective is to provide methods to rotate the turntable, index the turntable accurately and drive the carriages linearly with systems that avoid the hazards of the abrasive environment by reason of their design concept and the location of drives and services. Still another but equally important objective is to provide services electrical, hydraulic, and air to the drive system, rotational and linear, that does not require rotating joints, does not interfere with rotation of the turntable and whose source of supply is above the abrasive dirt environment. Yet another but equally important objective is a carriage linear drive system requiring no external drive mechanism cylinder, rack-and-pinion, or other means of locomotion.